Re: [google-cloud-sql-discuss] Re: PostgreSQL: to increase shared_buffers

Hi Alexander and thanks for feedback!

shared_buffers is a difficult param as it has performance vs stability / recovery time trade-offs and we don't want to compromise those.

We did some testing and found out that setting shared_buffers to around 30% of the instance memory yields best performance for tpc-b/c -like workloads while not compromising other features of the system.

So that's what we set shared_buffers to on sufficiently large instances (with > 3.5G ram as far as I remember).

Note that PostgreSQL will use OS-level disk buffers as well, so if your dataset fits in memory you are likely to see very little read operations regardless of value of shared_buffers.

All that said, we are certainly open for more tuning and we are eager to learn about different workloads. Would you be able to elaborate why do you think increasing shared_buffers benefit your workload?

Thanks!

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Vladimir Rusinov
PostgreSQL SRE, Google Ireland

Google Ireland Ltd.,Gordon House, Barrow Street, Dublin 4, Ireland
Registered in Dublin, Ireland
Registration Number: 368047

On Mon, May 1, 2017 at 10:10 PM, Aleksander Efremov <mr.efrem@gmail.com> wrote:

I execute the select query with the RegExp in condition on 2 million and above records and it spend much time.

вторник, 2 мая 2017 г., 9:05:13 UTC+4 пользователь Aleksander Efremov написал:

When you plan to inject this feature?

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